Back in 1533, artist Hans Holbein painted a piece he titled "The Ambassadors." The artwork is a double portrait as well as a still life, but there is something even more impressive in it that can only be seen from a certain perspective. If you stand to the right of the painting, you can see a skull. It serves as a memento mori, or a reminder of death, and many believe it is the artist's way of saying death is always hiding in plain sight.